


Unfinished

by thomastairparis



Category: The Last Hours Series - Cassandra Clare, The Shadowhunter Chronicles - Cassandra Clare
Genre: Angst, Angst and Feels, Canon Era, Character Death, Edwardian Period, Established Relationship, Heavy Angst, Illnesses, Letters, Love Letters, M/M, One Shot, Sad Ending, Sickfic, Slow Death, Weddings, alastair is extra grumpy, alastair playing piano, but this is sad so..., idk how to tag, no beta we die like men, thomas gets sick
Language: English
Status: Completed
Published: 2021-02-16
Updated: 2021-02-16
Packaged: 2021-03-17 11:07:13
Rating: Not Rated
Warnings: Major Character Death
Chapters: 1
Words: 3,971
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29470674
Author URL: https://archiveofourown.org/users/thomastairparis/pseuds/thomastairparis
Summary: Thomas gets re-diagnosed with the illness he had once suffered from as a child. Alastair struggles to come to terms with the very real possibility of losing him
Relationships: Alastair Carstairs/Thomas Lightwood
Comments: 17
Kudos: 34





	Unfinished

**Author's Note:**

> this is one of the longest one shots i've ever written, and truthfully its unedited, but honestly im quite proud of it

Alastair Carstairs closed his eyes, his fingers dancing lightly over the keys of his piano. It had been a birthday gift from Thomas Lightwood, his fiance of two months. He softly hummed along to his own playing until the door to his apartment being violently thrown open interrupted him. He turned, frowning and preparing to fix whomever it was with a glare.

His face quickly fell into one of concern, his heart contracting. He stood, storming over to where Matthew Fairchild, Christopher Lightwood, and James Herondale were holding Thomas between them all. Alastair demanded, “What happened?”

Thomas’s hazel eyes met his as he was being lowered onto the couch. His shirt was ripped open and his side was bandaged up neatly. “‘M fine…”

“You collapsed out of nowhere after killing that Raum demon,” James stated in a dry tone, crossing his arms over his chest. “You are  _ not _ fine.”

Alastair pushed his way through the merry thieves, lightly touching Thomas’s shoulder. “You collapsed? How? Are you ill?”

“I am quite alright,” his voice was a weary rasp. 

“We have already called James’s uncle Jem,” Christopher said, his brows furrowed as he studied Thomas. He looked over at Alastair with curious purple eyes. “Is he not your cousin?”

“He’s the son of my father’s brother, so yes, he would be my cousin,” Alastair snapped. He did not have much patience on his good days and the feeling of concern tightening his heart and threatening to choke him did not help matters much. Or at all.

He just looked back at Thomas, his fingers digging further into his shoulder, as if, by physically holding onto him, he could will him to be by Alastair’s side forever. 

Thomas fixed him with a soft, reassuring gaze. Perhaps Alastair was being a tad bit dramatic, but Thomas was one of the few people he had ever allowed himself to love and the prospect of anything ever happening to him filled Alastair with emotions he was not quite sure how to properly express.

~~~

It was the illness. The one Thomas had been diagnosed with when he was very young. It was back and it was worse than it had ever been. Thomas was not expected to last until the end of the year.

Alastair felt as though he were living a nightmare. He had never known grief like this, and Thomas was not even dead yet. The angel must have been laughing at the cruel joke that was Alastair’s life. How could he have to suffer through a bloody mess of childhood, put up with an awful relationship with a man who never truly cared for him, and finally find the kindest, most lovely man who was more wonderful than he had ever dreamed of, only for their days together to be limited? He might not have been the most tolerable person, but not even the most awful people alive did not deserve this.

Thomas was taking it all quite well. He still remained too stubborn to ask for assistance unless it was absolutely necessary and still acted like he was at the peak of health, but he had not broken down once. However, Alastair had broken down, in both frustration and devastation, more times than he was proud of.

He could not handle it, any of it. He couldn’t handle watching Thomas’s broad shoulders grow slimmer. He could not bear to watch him lose more of his appetite and energy with each passing day. It killed him to witness Thomas struggle to get himself out of bed and take careful, stumbling steps as he searched for some shreds of his remaining independence. It hurt to watch Thomas’s pride crumble as Alastair or one of his friends had to offer him assistance. 

Alastair stared out the bedroom window, thinking everything over. He glanced down, admiring the way the moonlight shone onto Thomas’s pale skin. He was without a shirt and laying on his stomach, his head burrowed in the crook of his arm. The blankets were pulled up to the middle of his back. They were two thick quilts, though Thomas was still shivering. 

Alastair sighed, pulling the blankets further up, the hollow feeling in his gut getting worse. He reached over, touching Thomas’s soft, sandy brown hair. He ran his fingers lightly through it and he could not help but wonder how many more times he would be able to do this. To sit up, awake, as his fiance slept peacefully beside him. 

Eventually, it would just be him, alone in a cold, empty bed for the rest of his life. It was not as though he would ever find another man to love him like Thomas did. He was not even deserving of Thomas’s love, how could he ever hope of finding someone else? 

Alastair did not know when the sobs started, or when they began to wrack his body as tears streamed hotly down his cheeks. He clamped a hand over his mouth, squeezing his eyes shut. He couldn’t wake up Thomas, he needed his rest.

He shoved the blankets off himself, quickly making his way out of the room. He fell to his knees in front of the fireplace. The flames were gone, disappeared into the night after no one had bothered to tend to them after they had gone to bed. 

Alastair stared into the embers, feeling useless. If he were good for anything, anything at all, he would’ve found some way to help Tom. But he was not good for anything. He was terrible, useless, and now utterly, utterly destroyed.

“Alastair?” A soft, tired voice came from the doorway.

And now he had been even more terrible. He had awoken Thomas. 

Alastair turned, wondering how pathetic he looked kneeling in front of the ashes. He wiped at his eyes, drawing in shaking breaths. “You should be asleep.”

Thomas was leaning against the wall, though not casually; it looked as if the wall was the only thing holding him up. His hazel eyes had dark circles etched deeply around them. He mumbled, “you’re crying.”

Alastair pushed himself to his feet, walking over to Thomas. “Do not worry yourself over me. Go back to sleep.”

Thomas’s face suddenly crumpled. Alastair sucked in a sharp breath as Thomas started to cry as well. He looked up at the ceiling, his face tilted so Alastair could no longer see it, and said in a ragged voice, “I was supposed to be fine. They  _ told me _ I was fine when I was 13. And then I had this fucking growth spurt,” he gestured at his tall frame. “And no one thought it was possible for me to get sick again. I was a burden all my life and now I am a burden once more and I hate it! I deserved…” his voice trailed off and he looked down, slipping down the wall.

Alastair reached out, catching him and drawing Thomas into his arms. He finished, “you deserved to live a full, happy life.”

Thomas did not say anything. Instead, he rested his chin on Alastair’s head, wrapping his arms around his shoulders. Alastair wrapped his arms around Thomas’s hips. They stood like that for a long time, mourning the lives they would never get to spend by one another’s sides. 

Alastair closed his eyes, burying his face into Thomas’s shoulder. He loved Thomas so much it lifted him up, making him feel as though he were flying. He was not prepared for crashing down when Thomas was gone and he could no longer soar.

~~~

Thomas knew Alastair was not handling his illness well. It had been three months and Alastair had gotten snappier and more impatient by the day. Aside from patrol and his daily long walks, he had begun to devote every second to Thomas’s needs and wants. If Thomas wanted Alastair to stay with him, he would. If he needed space, Alastair would read in their small drawing room until Thomas required his assistance again. 

Thomas was grateful for his beautiful, selfless fiance. He was not sure what he would do without Alastair. And, if he was being entirely honest, he was not sure what Alastair was going to do without him. 

But for now, he was going to make every last second between them count. He stood in front of the mirror on unsteady feet, cursing his own reflection. He hadn’t looked this sickly since he was 14. He had done 200 pushups a day and suffered terrible growing pain since then.

His skin was not supposed to look so sallow and pale. His eyes were not supposed to be so void of life. He was not supposed to be so slim, all the muscles he had worked so hard to gain weren’t supposed to be gone from lack of exercise over the past three months.

At least Matthew had been excited to go shopping for him, bringing back a nice golden waistcoat patterned with white runes and an expensive black coat. At the very least, no matter how ill he looked, the outfit improved his appearance just slightly. It was good enough, not perfect, but good enough.

Thomas would have to ensure everything else was perfect to make up for it.

~~~

Alastair had not stopped complaining since his sister had dragged him out the door. He was surprised she had not stabbed him yet. 

Eventually, Cordelia whirled around to face him and snapped, “will you  _ shut up? _ ”

He glared at her. “I need to get home.”

Cordelia’s eyes softened with sympathy. “You shall get to see Thomas soon, I promise.”

“I want to see him now,” he grumbled. He sounded like a moody toddler, though that was far from his biggest concern. He had been gone for almost two hours and his overwhelming worry was threatening to quite literally kill him. Perhaps Thomas was fine, but what if he was not? What if he was hungry or wanting for a walk, a change of clothes, or a bath?

Cordelia sighed, touching Alastair’s shoulder. “He is very, very lucky to have you. But you are making yourself sick with worry.”

“What else would I do if not worry?” Alastair demanded. “Thomas is my everything and I am  _ losing _ him. He’s  _ dying _ , Layla, and there is nothing I can do to stop it.”

Cordelia hesitated, before stepping forward and hugging Alastair. He froze. It had been so long since they had hugged, but, he admitted to himself, he may have needed this. 

Cordelia softly spoke, “you do not deserve this. Neither of you do.”

Alastair scoffed, but he slowly hugged her back. “I’ve come to learn there is no use in mulling over what anyone does or does not deserve. If we all truly got what we deserved, I would be the one dying, not him.”

Cordelia pulled back, looking as though she was about to respond, when Alastair turned on his heels and started to storm away. Cordelia sighed, grabbing at his arm. When she spoke, her voice was a bit sadder, “Wait, Alastair joon, where are you going?”

“Home.”

“He is not there,” she admitted.

Alastair quickly spun back around to face her. He narrowed his eyes, feeling his patience quickly slip away. “What do you  _ mean _ , ‘he is not there?’” His voice was furious and demanding, even to himself.

His sister flinched. “He’s at the institute. It was meant to be a surprise.”

“What was meant to be a surprise, Cordelia?” He snapped, purposely using her name instead of the nickname “Layla” he always commonly referred to her as. 

She set her jaw, stubbornly lifting her chin. Her dark eyes flashed at him. “I suppose you will have to come to the institute and discover it for yourself.”

Alastair despised being outsmarted. Being outsmarted by his little sister was a sharp, well delivered blow to his pride. His voice was hard, “fine.”

~~~

Thomas was sure he was going to pass out, though for the first time in months, it would not be from lightheadedness. It would be from the flutter of nerves, love, and excitement in his heart. By the angel, he hoped Alastair would like this.

“You look handsome.” It was his mother’s voice.

Thomas turned to her, hating the sad look in her eyes, and hating knowing he was half of the reason for it. He smiled softly. “Thank you, mama.”

Sophie turned her face away, taking a deep breath. Thomas leaned over, hugging his mother. He hugged her for several moments, feeling the flutter of feelings calm in the comfort of his mother’s arms. 

Thomas pulled back. “Will you be my suggenes?”

Sophie nodded, tears building in her eyes. “Yes, Tom, of course.”

~~~

Alastair had been shoved into an institute bedroom. It was rather dusty, making him wonder if the Herondales had a sufficient maid or if they voluntarily decided to leave their rooms to rot and decay. The only item in it, aside from the distasteful furniture, was a suit jacket. It was white, decorated nicely with delicate golden runes. 

_ Marriage runes _ . 

“So that is the surprise,” Alastair mumbled to himself, as pulled off his gloves, setting them on the chest of drawers. He lightly ran his hand over the jacket. It felt expensive in his hands.

He pulled it on, checking his reflection in the filthy mirror. He looked quite passable, though his hair had fallen messily out of it’s carefully managed style and was now fringing over his forehead. 

Alastair left the room, ducking out into the hallway. He’d expected Cordelia to be waiting for him, but she was no longer there. Instead, Thomas was waiting, leaning heavily on a cane. He looked entirely and ridiculously handsome, in a long black coat over a golden waistcoat. His hair had been neatly cut.

Thomas looked up, his eyes meeting Alastair’s. “Cordelia said you were angry with her when she stopped you from coming home. I thought it would be best if I ensured you were calm before…well...” 

The words were left unspoken:  _ The wedding. _

Alastair reached out, taking his hand. He was at a loss for words, nothing seemed as though it would quite capture the loving ache of his heart. He stepped forward, setting his hand on Thomas’s neck and drawing him down for a soft kiss. “Thank you.”

Thomas shook his head. “There is no need to thank me. I thought, since I had been the reason we have been cooped up in the flat for three months, it is high time I do something to brighten both of our moods. And besides,” he added with a small smile. “We have been engaged for five months.”

Alastair felt his heart soar for the first time in three months. He stepped back, shaking his head as he stared up at Thomas in wonder. “How fucking dare you be so bloody perfect all the time?”

Thomas rolled his eyes. “I am far from perfect and you know that. If I were perfect, I would not be…”  _ Dying. _

Alastair fixed him a firm look. “That is not your fault. You are perfect, for everything you say or do is perfect.”

Thomas looked down at his cane, before looking back at Alastair. His hazel eyes were tender. “You best save something for the vows.”

“Vows?” Alastair asked skeptically. “You throw a surprise wedding and expect me to come up with vows? We have what? Five minutes? You must be joking, Tom.”

Thomas grinned. “I was only kidding. I thought we could perhaps…” his voice grew hesitant, “write vows later and exchange them in private? I am not the most fond of speaking in front of others anyways.”

Alastair reached up, resting his hand on Thomas’s shoulder. “As I said before, you are much too perfect.” 

Thomas drew him in to gently kiss his forehead. “I disagree, though I am quite sure we have no more time to argue. Let’s go get married.”

~~~ 

The ceremony was, quite frankly, a blur. Cordelia took up the part of Alastair’s suggenes and Thomas’s mother was Tom’s. Will Herondale was the one performing the ceremony and he had quite effortlessly slipped in several jokes about Thomas’s childhood. 

If Alastair was being honest, he was not paying much mind to Mr. Herondale, or the guests. His attention and thoughts were reserved for Thomas and Thomas alone. Alastair was studying the bright, loving gleam in his hazel eyes and the quirk of his soft lips. He was truly quite annoyed when he had to be snapped out of his thoughts to apply the marriage rune.

Alastair held the stele carefully, twirling it once between his fingers as Thomas shrugged off his coat and handed it to his mother. He released his cane to unbutton his waistcoat and shirt, slipping his shirt down his right shoulder. Alastair touched Thomas’s bicep, a lump forming in his throat as he carefully traced the marriage rune on Thomas’s pale skin.

He cleared his throat, reciting, “Set me as a seal upon thine heart, as a seal upon thine arm: for love is strong as death.” His voice threatened to break on the last word, but he stubbornly persisted.

Thomas glanced at the dark swirls, his eyes widening. He quickly pulled his shirt back on and Alastair reached to help him button it as Thomas leaned back on the cane. Alastair then unbuttoned his own shirt, letting it fall down his shoulder. There was a draft in the institute that breezed over his bare skin and he suppressed a shiver.

The familiar pain of the stele greeted his bicep, as Thomas slowly traced the rune. 

“Set me as a seal upon thine heart, as a seal upon thine arm: for love is strong as death.”

Thomas stepped back and Alastair looked down, admiring the rune. It was stark black against the brown of his skin and drawn beautifully. The lump in his throat only grew as Alastair tugged his clothes back on. 

He stared up at Thomas, his heart full. They may only have a few more months with each other, but right now, standing up on an altar, that did not matter. All that mattered was that Thomas was promising to spend the last of his limited days by Alastair’s side. It was practically incomprehensible.

Why would Thomas Lightwood, a man who was so good, and loving, and  _ lovely  _ want to marry someone like Alastair? Someone broken and grumpy who had a knack for being cruel when he felt threatened. He would never figure it out, though he was eternally grateful for this man. For Thomas.

~~~

_ Tom, _

_ We agreed to write our vows as letters and I feel like this would be the perfect time to admit that this is not the first letter I’ve ever written to you. Do you remember the Townsends’s musicale about a year ago? How you, quite rudely, asked me to either not attend or inform you if I had any plans to? I hadn’t sent any of my responses, but I wrote four. Each was more horrible than the last. I have faith that this one will be better. _

_ I suppose I should start with telling you how very fortunate I am to be your husband. You are the most incredible person I have ever known and I do not understand how you think me even slightly deserving of your love, after everything. But, in the short time we will have each other, I will do everything I can to ensure you do not regret your choice as your days dwindle to an end. I am not quite sure how I will manage that, but if you leave me with a heart of regret I will never forgive myself.  _

_ I love you and I will continue to love you, not just ‘til the end of your days, but until the end of mine. Kharâbetam. _

_ Alastair _

~~~

Alastair woke up to what felt like a fire. It was not. It was Thomas’s bare, fevered skin. He was groaning in Spanish under his breath and shaking. Alastair propped himself up on his elbow, touching Thomas’s forehead. “ _ Fuck!” _

An hour later there were three silent brothers in their apartment. Alastair was sitting on the couch, bracing himself on his knees. He had a mug of tea in his hands, though he was not sure how it found itself there. It was cold, mimicking the awful feeling in his chest.

“Let me see him,” his voice was quiet, barely audible. He looked up at the silent brother nearest to him. It was his cousin, Jem. “Please, I need to see him.”

Another silent brother, Alastair was fairly sure he was Brother Enoch, held up a hand. They seemed to be silently conversing, something Alastair had no time for. He demanded. “Let me see him! Let me…”

_ Say goodbye. _

Jem seemed to be pleading. Enoch spared at glance at Alastair.  _ “There is little hope for the Lightwood gentleman. Are you positive this is what you wish?” _

Alastair nodded, feeling choked up with tears. “I need to see him.”

The silent brothers parted, giving him an entrance to the door. He stood, stumbling to the bedroom. Thomas was laying there, one hand resting on his abdomen, the other lying limply by his side. His eyes were closed and his breaths came out shallow. 

Alastair reached over, resting his hand over where Thomas’s was sitting on his tummy. “Tom,” he croaked out.

Thomas stirred and his eyes fluttered open. He turned his head to look at Alastair, smiling weakly. “Hello, love.”

Alastair squeezed his hand. “Are you truly leaving me?”

Thomas closed his eyes, breathing deeply. “I am not sure...if I have much...choice.”

Alastair sunk to his knees beside the bed, his wedding rune aching over his heart. Or, perhaps, it really was his heart that was aching. He could not quite be sure. “You  _ cannot _ leave me, do you understand? _ I can’t lose you! _ ”

Thomas stared at him for a long moment before he groaned, turning away. He struggled out, “it is a shame that...that I never got to finish my vows.”

Alastair shook his head. “I do not care about stupid vows! You’re ill, I understand that you struggled to finish.”

Thomas slowly turned back to look at Alastair. “I still...think you should read it. It is in my pants drawer. I wish...for you to...remember me.”

Alastair was not sure if he was choking on a sob or a laugh. He half buried his face into his outstretched arm, not bearing to fully face his dying husband. “Remembering you will be the easiest thing I will ever have to do, Thomas Lightwood.”

Thomas shakily lifted their joined hands to his lips, kissing Alastair’s knuckles. “I do not...wish for your unhappiness.” He cupped Alastair’s cheek with his free hand. “Please, Alastair, be happy…”

He turned his face away for the last time, muttering, “Kharâbetam.”

Alastair lifted his head, squeezing Thomas’s hand as tears furiously ran down his cheeks. “Tom?  _ Thomas? _ Thomas  _ please… _ I cannot live without you...” 

He kept talking, waiting for an answer that would never come. There would never be an answer from his Thomas again.

~~~

_ Alastair Carstairs, _

_ This is not a goodbye letter. It’s a love letter that I am using as a means to say goodbye, for how could I possibly say goodbye to the man I have been in love with since I was 14? I have since learned that I cannot. It seems rather impossible. Almost as impossible as you learning to love me back. I used to think that you did not deserve my love. But now, I know that you deserve more than to love a dying man.  _

_ You deserve all the love and adoration in the world, for you are _

  
__ **[letter unfinished]**

**Author's Note:**

> please let me know what you thought <3 also PLEASE dont kill me for this


End file.
